I view, then, the high roof as partly the result of climate and partly of the æsthetic tendency of the style. But is it to be considered as an essential characteristic of Gothic architecture? By no means. The true characteristic of the style is _liberty_; and in the roof, as in every other feature, perfect freedom is reserved; so that we find roofs varying from almost perfect flatness to a very high pitch, a preference being given, _cæteris paribus_, to the high roof where there was not some decided objection to its use. In internal construction also the roof was founded on rational principles, good construction being always considered before beauty, but the latter made very generally to result from it. Gothic timber roofs would form a subject which could hardly be done justice to under one or two lectures, so I will not go farther into them now. Modern carpentry has shown us how to construct roofs with less timber than was used in these structures (there was then less necessity for the economy of timber), but we have never done anything to compete with the noble pieces of ornamented carpentering bequeathed to us by our Mediæval forefathers. As to covering of roofs, I may just mention, in passing, that though the Mediæval builders made use of every material which it is customary to use for this purpose, there are several which cannot be made use of with any but a high pitch, and are therefore unusable with low roofs such as are used in other styles, as, for instance, plain tiles, ordinary stone slate, shingle, and thatch. The next point in the _rationale_ of Gothic architecture is one which I by no means claim as its peculiar property, inasmuch as it is common to all _good_ architecture, though certainly our style is somewhat pre-eminent in its adoption of it. I refer to that general principle of ornamentation which trusts mainly for beauty to the useful and constructive features of the building, rather than to those which are introduced directly for appearance. Thus, in a noble Gothic building, the ornamental character arises from a greater or less richness in the _doorways_, in the _windows_, the _buttresses_, the _cornices_, _parapets_, or other parts needful for the uses or construction of the building. This belongs to all noble architecture, but is more thoroughly, I think, carried out in Gothic than in other styles, and perhaps less so in modern Italian, especially in what is commonly called Paladian, than in any other. I do not lay claim to it as an argument in favour of one style above another, for all _ought_ to possess it alike; but the absence of it in a very great deal of modern architecture is at least a proof that much reformation is needed among ourselves; and the strong degree in which it was adopted as a maxim by the Gothic architects is a proof of the reasonableness of the principles on which they acted.